Place sliced zucchini and onion in a bowl and mix in dressing. Let marinate for one hour. Preheat grill to low. Remove zucchini and onions and place alternately on skewers. Save the salad dressing remaining in the bowl. Grill the skewered vegetables, turning and basting with the salad dressing occasionally. Cook until they are soft but not quite ready to fall off the skewer (approximately 30 minutes). Remove the vegetables from the skewer and place in a covered container in order to keep them slightly warm. Prepare the Pesto Spread by mixing the mayonnaise and the pesto sauce in a small separate bowl. Set aside. In a separate bowl thoroughly mix the ground chuck, mushrooms, garlic salt, vinegar, Italian seasoning, romano cheese and black pepper. Form the mixture into six evenly sized patties. Preheat the grill to medium-low, then grill the burgers to desired doneness (approximately 12 minutes total for medium), flipping them half way through the cooking time. Two minutes before the patties are cooked to completion, place one slice of asiago cheese on each patty. Then place the rolls cut-side down on a cooler part of the grill. Cook the rolls until they are just beginning to brown (approximately 2 minutes). Remove the roasted peppers from the bottle and dry them by pressing them between paper towels. Slice the peppers in any size so that they can be split evenly among the six burgers. To assemble each burger, spread 1 tablespoon of the Pesto Spread on each half of the roll. Lay the patty on the bottom of the roll, place one-sixth of the roasted peppers on the patty and then top with one-sixth of the zucchini and onions. Place the other half of the roll on top and mangia!